The subject matter disclosed herein relates to a method and system for inspecting a rail profile using phased array technology.
Nondestructive testing devices can be used to inspect test objects to detect and analyze anomalies in the objects. Nondestructive testing typically involves placing one or more probes on or near the surface of the test object in order to perform testing of the underlying structure. One method of nondestructive testing employs ultrasonic acoustic waves.
Generally, an ultrasonic testing system includes an ultrasonic probe for transmitting and receiving ultrasonic acoustic waves to and from a test object, and a probe cable for connecting the ultrasonic probe to an ultrasonic test unit that includes a display for viewing the test results. In an ultrasonic testing system, electrical pulses are fed from the ultrasonic test unit to an ultrasonic probe where they are transformed into acoustic pulses by one or more ultrasonic transducers (e.g., piezoelectric elements) in the ultrasonic probe. During operation, electrical pulses are applied to the electrodes of one or more ultrasonic transducers, thus generating ultrasonic acoustic waves that are transmitted to the test object to which the probe is coupled, either directly on the surface of the test object or, e.g., through water in which the test object is immersed. Conversely, when an ultrasonic acoustic wave is reflected from the test object and contacts the surface of the ultrasonic transducer(s), it causes the transducer(s) to vibrate, generating a voltage that is detected as a received signal by the ultrasonic test unit. As the ultrasonic acoustic waves pass through the test object, various reflections, called echoes, occur as the ultrasonic acoustic waves interact with anomalies within the test object.
When inspecting an object with a conventional, single element ultrasonic probe, the location and orientation of the ultrasonic probe is changed several times to inspect different regions of the object. In order to inspect the full volume of the object, it may be necessary to scan the object dozens of times at different angles and locations, each time relocating and reorienting the ultrasonic probe, which can be time consuming. Alternatively, multiple single element ultrasonic probes can be used to inspect different regions of the object, positioning each of the probes at different locations on or near the object. However, the use of multiple single element ultrasonic probes can make the test system expensive and positioning the multiple single element ultrasonic probes based on the unique shape of the test object can require complex testing mechanics.
For example, ultrasonic inspection is currently used to inspect a rail profile 100 for volumetric defects. As shown in FIG. 1, a rail profile 100 includes a head 110, a web or web interface 120, and a foot/base 130; the web 120 interconnects the head 110 and the base 130. A rail profile (i.e., rail) may be made of steel or another metal, and used (e.g., in parallel pairs) as a track for a rail vehicle.
In order to adequately inspect the head 110, the web 120, and the foot/base 130, a significant number of conventional, single element ultrasonic probes must be used (e.g., 15-20) to cover the test areas. In a conventional automated ultrasonic testing system for inspecting a rail profile, squirter technology is used to provide water coupling between the single element ultrasonic probes and the surface of the rail profile. Even using all of those single element ultrasonic probes at particular locations with respect to the rail profile 100, there are portions of the rail profile 100 that are not inspected. Furthermore, since there are dozens of different designs and geometries for rail profiles, the specific locations of the single element ultrasonic probes with respect to the different rail profiles need to be determined and extensive mechanical adjustments are required for each different rail profile.